Journey in dream!

Most adults need seven to nine hours of sleep to recuperate from physical exertion, as well as to consolidate learning and memory. Sleep is essential for proper psychological and physiological functioning. Research on rats has found that a week of no sleep leads to loss of immune function, and two weeks of no sleep leads to death. Sleep has been linked to psychological, emotional, and mental recovery, as well as learning and memory. Recent research shows that sleep is vital in consolidating memories, both intellectual and physical. Sleep deprivation can inhibit your productivity and your ability to remember and consolidate information. It can also lead to serious health consequences such as increased risk of heart disease and obesity. The amount of sleep we need varies depending on multiple factors: age, physical condition, psychological condition, or energy exerted.

Research has uncovered a number of ways that a lack of sleep affects our well-being. Sleep deprivation negatively affects brain chemistry, growth, healing, attention, memory, and the ability to operate machinery, among other things. Sleep deprivation can cause both physical and mental illness, such as diabetes, depression, and psychosis, and in extreme cases, it can cause hallucinations and death. Therefore, sleep requirements depend on the individual.

sleep deprivation is related to: higher rates of motor vehicle accidents; higher BMI, an increased likelihood of obesity, and increased risk of diabetes and heart problems; higher risk for depression and substance abuse; decreased attention, slower reaction times, and the inability to remember new information.

Sleep proceeds through multiple cycles of non-REM (3 stages) and REM per night, with each full cycle lasting between 90 and 110 minutes. REM sleep is characterized by partial paralysis, vivid dreaming, and an EEG that resembles waking brain activity. It is also referred to as paradoxical sleep because the sleeper, although exhibiting waking-state EEG waves, is harder to arouse than at any other sleep stage. Sleep is divided into five different stages: Stages 1, 2, 3, 4 and REM. REM sleep is characterized by a high level of activity in the brain, as well as a temporary paralysis of the muscles. During REM, our heart rate increases, our breathing speeds up, and our eyes move back and forth beneath our lids. A small 2015 study found that our eye movements actually mimic those of when we’re awake, only instead of responding to images out in the world, they’re responding to dreams. REM sleep is responsible for vivid dreams. We may dream during other sleep stages, but those dreams will feel fragmented; the types of dreams that have elaborate storylines and complex imagery are fueled by REM.

Dream lucidity is the awareness that you are dreaming. This awareness can range from a faint recognition of the fact to a momentous broadening of perspective. Lucid dreams usually occur while a person is in the middle of a normal dream and suddenly realizes that they are dreaming. This is called a dream-initiated lucid dream. A wake-initiated lucid dream occurs when you go from a normal waking state directly into a dream state, with no apparent lapse in consciousness. In either case, the dreams tend to be more bizarre and emotional than regular dreams. Most importantly, you will have at least some ability to control your "dream self" and the surrounding dream.

We sleep in cycles. We first experience REM 70 to 90 minutes after falling asleep, and we go through a number of sleep cycles throughout the night, with REM cycles increasing in length as the night goes on. People are best able to remember their dreams when awakened from REM (as opposed to naturally shifting to other parts of the sleep cycle). If you awake unnaturally (through an alarm, for example), and the dream you just had feels unusually vivid to you, it may be because you were still in a REM stage when you woke up. Because REM sleep and dreaming are a critical component of sleep for all mammals, including humans, poor sleep-quality is increasingly being associated with the onset of various brain disorders such as Alzheimer's diseases (AD) and Parkinson's disease.

Statistically, REM sleep is significantly perturbed in Alzheimer's. The results from this study suggest that disruption of REM sleep may exacerbate memory impairments observed in AD, the researchers say.